HST: DMU or LHCS

[theblackwatch]

I believe it was in 1988 when BR decided to reclassify HSTs away from DEMUs, hence the change in the Platform 5 books to reflect this.

Even now, 'the railway' itself seems confused and can't make its mind up fully - GWR's own rolling stock booklet, dated December 2019, refers to Class 255 in it....

 

[anthony kelly]

When the HSTS were first introduced they were the class 43s and were called power cars then They ran in strict set fomation. Some years later they were reclassified to class 43 locomotives so they could be swapt from set up set but they were never called dmus . Dmus have bus engines or like underneath the train not power cars/ locos either end

 

[Mitchell Hurd]

Brilliant question - apparently the Mark 3's were in affect multiple units. This would explain why before, when you're in an HST Mark 3 coach, they sound there's a silent engine underneath which you can't feel. On a few occasions I've been in HST's (Coach D) that sounds ike across between a jet plane and an old classic car on the PS1 game Driver 2.

 

[Mitchell Hurd]

Semi-fixed formations with multiple traction motors controlled from a single desk at either end. Sounds like a MU to me.

I remember back on Saturday 9th September 2017 getting off the 08:15ish from Didcot Parkway at Totnes and videoing it leave - the Mark 3's sounded similar to a Class 319.

 

[Helvellyn]

When the HSTS were first introduced they were the class 43s and were called power cars then They ran in strict set fomation. Some years later they were reclassified to class 43 locomotives so they could be swapt from set up set but they were never called dmus . Dmus have bus engines or like underneath the train not power cars/ locos either end

They were DEMUs for Diesel Electric Multiple Units and hence the 2xx unit class.

All the Southern Region 20x DEMUs had one or two coaches with an above floor engine and the remainder being trailers. Plus plenty of first generation DMUs had trailer cars with no engine underneath the floor.

 

[norbitonflyer]

The term "multiple unit operation" can also refer to two locomotives under the control of one driver.

We mustn’t forget when the mark 4 coaches were first built, there was a class 91 on one end of the coach rake with a class 43 at the other end (both producing power) so the class 43s are not tied only to mark 3 coaches. .

On the contrary, it was because Class 91 production was running ahead of Mark 4 production, so it was a rake of (HST) Mark 3s, not (IC225) mark 4s between the class 91 and the class 43. The provision of an HST power car was necessary to provide power for aircon etc to the carriages because the Class 91 couldn't - because the carriages were not wired for loco haulage.

I can't think of a DMU that has a loco car that doesn't carry passengers.

Class 755? (also, of course class 128, but that does carry a payload)

A DMU, for me, involves some engines under the floor of some coaches in a train of carriages put together.

I can't think of any DMU that is more than 2 coaches that has 2 engines (or engine gubbins) or less.

No underfloor engines in classes 201-207, 210, 755. And class 204 - 207 were three-car units with just one engine in each unit.

 

[Merle Haggard]

This might have been already mentioned, but I did check & couldn't see the point raised before..
The codes for coaches in HST all start 'T' (for trailer).
Former loco-hauled stock modified to work in HSTs is reclassified from, for example, 'FO' to 'TF'.
But this just muddies the waters...

 

[themiller]

On the contrary, it was because Class 91 production was running ahead of Mark 4 production, so it was a rake of (HST) Mark 3s, not (IC225) mark 4s between the class 91 and the class 43. The provision of an HST power car was necessary to provide power for aircon etc to the carriages because the Class 91 couldn't - because the carriages were not wired for loco haulage.

Sorry, I’m sure I’ve made this mistake before on this forum. The old brain cells are becoming temperamental!

 

[43096]

Thank you! I was doing it all off memory. As you say, having 43151/43152 as spare made sense but at what point did 43152 move to become an Eastern Region power car? (It was NL based by 1986 and named St. Peter's School York AD627)

The book of numbers says 43152 was transferred to Neville Hill in early 1984, going back to the Western in June 1991, just in time for it to receive ATP equipment. I have seen it suggested that 43152 didn't get GEC motors as planned due to the chronic unreliability of those motors when new, and it received Brush traction motors with the GEC motors going under 43180. It may well have lasted like this until privatisation when they were swapped over as 43180 was a Porterbrook power car and would have been the only GEC-fitted example in their fleet.

With regards Diagram numbers for the power cars I am assuming GB501 was used for the two prototype power cars when they became 43000/43001 as part of 252001?

Oh, as an aside the fact that 41001 became 43000 when it was reclassified as a Class 252 should show the intent that it had become a DEMU - locomotives are not numbered xx000, only coaching stock and multiple unit vehicles.

I would think that is correct for the diagram numbers - don't think I've ever seen the diagram numbers quoted for the Class 252.

The rule for locomotives was that sub-classes didn't begin with xxx00, so the ETH 47s began at 47401, but 47500 was fine as it wasn't a new sub-class. This was broken when 31400 and 47300 were created. Of course, "41001" now breaks the rule, being classified on the national vehicle register as a Class 43/9 locomotive, numbered 43000.

 

[43096]

When the HSTS were first introduced they were the class 43s and were called power cars then They ran in strict set fomation. Some years later they were reclassified to class 43 locomotives so they could be swapt from set up set but they were never called dmus .

They didn't run in strict set formation. Almost from day one formations were variable with power cars from different sets (and spare power cars) formed together. Whilst the Western Region tried to keep the sets together - it made it easier when sending sets up to Derby for shopping as the complete set could go with trailers to Litchurch Lane and power cars to the loco works - the Eastern very quickly gave up on keeping power cars with their allocated sets.

For example by the end of November 1976 - just weeks after the 125mph service began - set 253002 had power cars 43030/031 (rather than 43004/005) and set 253005 had 43027 in place of 43011.

 

[theblackwatch]

For example by the end of November 1976 - just weeks after the 125mph service began - set 253002 had power cars 43030/031 (rather than 43004/005) and set 253005 had 43027 in place of 43011.

And on the Eastern, they were mixed on 'Day 1'. The first timetabled HST service out of King's Cross was formed of set 254006, but with power cars 43057 (254001) and 43061 (254003). Despite that, they did keep them reasonable correct for a while, particularly for works visits - I think the first set to be sent to Derby without the correct power cars was 254010, which went with 43075/79 (rather than 43074/75) around May 1980.

 

[delt1c]

There is no question that when introduced HST's were clasified as DEMU's, ask anyone who was around at the time. The power cars were later reclasified as loco's and it was convienient to retain the 43xxx numbers applied and reclasify them as 43's. As for fixed formations, whilst this was the intention but didnt happen ( trailers often swapped), this was no different from most DMU's of the time.

 

[pdeaves]

And on the Eastern, they were mixed on 'Day 1'. The first timetabled HST service out of King's Cross was formed of set 254006, but with power cars 43057 (254001) and 43061 (254003). Despite that, they did keep them reasonable correct for a while, particularly for works visits - I think the first set to be sent to Derby without the correct power cars was 254010, which went with 43075/79 (rather than 43074/75) around May 1980.

I don't remember where I saw it now (probably some railway journal) but there exists at least one picture of two HST power cars at Kings Cross buffer stops, side by side, both carrying the same nose end set number.

 

[theblackwatch]

I don't remember where I saw it now (probably some railway journal) but there exists at least one picture of two HST power cars at Kings Cross buffer stops, side by side, both carrying the same nose end set number.

Think I've seen more than one picture...am sure I saw one of a pair of 253023s at Paddington once!

 

[Mag_seven]

I don't remember where I saw it now (probably some railway journal) but there exists at least one picture of two HST power cars at Kings Cross buffer stops, side by side, both carrying the same nose end set number.

Think I've seen more than one picture...am sure I saw one of a pair of 253023s at Paddington once!

How on earth did spotters cope with that?

 

[xotGD]

How on earth did spotters cope with that?

Easy for loco spotters - they just ignored them!

Unit spotters who do it 'properly' do it by vehicle number rather than set number anyway, to deal with formation changes.

 

[43096]

Easy for loco spotters - they just ignored them!

Until they come back to their notes 30+ years later with “what were the power cars on date .....” questions.

 

[hexagon789]

When the HSTS were first introduced they were the class 43s and were called power cars then They ran in strict set fomation. Some years later they were reclassified to class 43 locomotives so they could be swapt from set up set but they were never called dmus . Dmus have bus engines or like underneath the train not power cars/ locos either end

Not quite, wgen introduced the production sets were classified as 253 (2+7) or 254 (2+8) the power cars were simply 43xxx number vehicles.

 

[hexagon789]

Brilliant question - apparently the Mark 3's were in affect multiple units. This would explain why before, when you're in an HST Mark 3 coach, they sound there's a silent engine underneath which you can't feel. On a few occasions I've been in HST's (Coach D) that sounds ike across between a jet plane and an old classic car on the PS1 game Driver 2.

Not really. The entire train was a "multiple unit", the Mk3s were simply the trailers.

Besides which the Mk3a and 3b vehicles are most definitely not multiple units, they are loco-hauled coaching stock.